From f83ffe578db6298bee4ee79ebfbdd58210dcce87 Mon Sep 17 00:00:00 2001
From: superatrain <superatrain@gmail.com>
Date: Tue, 18 Dec 2012 21:08:27 -0500
Subject: [PATCH] Implemented ternary operator.

---
 Graphics/Implicit/ExtOpenScad/Default.hs     |  7 ++++++-
 Graphics/Implicit/ExtOpenScad/Parser/Expr.hs | 17 +++++++++++++++--
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/Graphics/Implicit/ExtOpenScad/Default.hs b/Graphics/Implicit/ExtOpenScad/Default.hs
index 6869fa07..09c85055 100644
--- a/Graphics/Implicit/ExtOpenScad/Default.hs
+++ b/Graphics/Implicit/ExtOpenScad/Default.hs
@@ -85,7 +85,8 @@ defaultPolymorphicFunctions =
 		(">=", toOObj ((>=) :: ℝ -> ℝ -> Bool) ),
 		("<=", toOObj ((<=) :: ℝ -> ℝ -> Bool) ),
 		("==", toOObj ((==) :: OVal -> OVal -> Bool) ),
-		("!=", toOObj ((/=) :: OVal -> OVal -> Bool) ), 
+		("!=", toOObj ((/=) :: OVal -> OVal -> Bool) ),
+		("?", toOObj ( ternary :: Bool -> OVal -> OVal -> OVal) ),
 		("list_gen", toOObj list_gen)
 	] where
 
@@ -196,3 +197,7 @@ defaultPolymorphicFunctions =
 				[fromIntegral (ceiling a), fromIntegral (ceiling (a+b)).. fromIntegral (floor c)]
 		list_gen _ = Nothing
 
+		ternary True a b = a
+		ternary False a b = b
+
+
diff --git a/Graphics/Implicit/ExtOpenScad/Parser/Expr.hs b/Graphics/Implicit/ExtOpenScad/Parser/Expr.hs
index f6175fbf..6da182c9 100644
--- a/Graphics/Implicit/ExtOpenScad/Parser/Expr.hs
+++ b/Graphics/Implicit/ExtOpenScad/Parser/Expr.hs
@@ -179,8 +179,7 @@ expression n@3 =
 		expr <- expression $ n+1
 		return expr
 	) <|> try (expression $ n+1)
-expression n@2 = try (expression $ n+1)
-expression n@1 = 
+expression n@2 = 
 	try ( do
 		firstExpr <- expression $ n+1
 		otherComparisonsExpr <- many $ do
@@ -201,5 +200,19 @@ expression n@1 =
 			[x] -> x :$ exprs
 			_   -> collector "all" [(comparisons!!n) :$ [exprs!!n, exprs!!(n+1)] | n <- [0.. length comparisons - 1] ]
 	)<|> try (expression $ n+1)
+expression n@1 = 
+	try (( do 
+		a <- expression (n+1)
+		genSpace
+		string "?"
+		genSpace
+		b <- expression n
+		genSpace
+		string ":"
+		genSpace
+		c <- expression n
+		return $ Var "?" :$ [a,b,c]
+	) <?> "ternary")
+	<|> try (expression $ n+1)
 expression n@0 = try (do { genSpace; expr <- expression $ n+1; genSpace; return expr}) <|> try (expression $ n+1)